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Abstract:

Imaging systems including a multiple focal spot x-ray source adapted to
irradiate an object with a series of angularly displaced x-ray beams, one
at a time, without substantial rotation or translation of the multiple
focal spot x-ray source are provided. Such systems also includes a
detector adapted to receive at least a fraction of the angularly
displaced x-ray beams after being attenuated by the object to produce at
least two x-ray projection images of the object. The imaging systems also
include a processor adapted to shift and add the at least two x-ray
projection images to bring at least two planes of the object into focus,
one at a time.

Claims:

1-21. (canceled)

22. An imaging system, comprising: a multiple focal spot x-ray source
configured to generate at least two x-ray beams and to project each of
the generated x-ray beams at a different angle one at a time toward a
field of view without substantial rotation or translation of the multiple
focal spot x-ray source; a detector opposite the multiple focal spot
x-ray source relative to the field of view and configured to receive at
least a fraction of the projected x-ray beams from each of the different
angles and to produce at least two x-ray projection images of the field
of view corresponding to each of the different angles, wherein each of
the x-ray projection images are configured to be shifted with respect to
one another and added to reconstruct a plane of the field of view.

23. The imaging system of claim 22, wherein the multiple focal spot x-ray
source comprises an anode and a cathode and is configured to generate the
at least two x-ray beams by generating a current flow between the cathode
and the anode.

24. The imaging system of claim 22, further comprising a controller
configured to inspect the reconstructed plane of the field of view to
determine the presence or absence of a defect in an object within the
field of view.

25. The imaging system of claim 24, further comprising a controller
configured to activate a separate and distinct anode and cathode pair to
generate each of the at least two x-ray beams.

26. The imaging system of claim 22, further comprising a table configured
to be translated from a first position to a second position so as to move
an object positioned on the table within the field of view.

27. The imaging system of claim 26, wherein when the table is translated
from the first position to the second position, the multiple focal spot
x-ray source is configured to generate and project at least two
additional x-ray beams at different angles one at a time toward the
object without substantial movement of the multiple focal spot x-ray
source and wherein the detector detects at least a portion of the at
least two additional x-ray beams after being attenuated by the object to
produce an additional at least two x-ray projection images of the object.

28. The imaging system of claim 22, wherein an object is placed between
the x-ray source and the detector such that the object is substantially
covered by the field of view of the detector, and wherein the at least
two projection images of the object are configured to be reconstructed to
provide volumetric slices of the object.

29. A laminography inspection method, comprising: providing an object to
an inspection area; irradiating the object with at least two x-ray beams,
each incident on the object from a different angle, one at a time, to
generate a series of angularly displaced images of the object, wherein
the at least two x-ray beams are generated by a stationary multiple focal
spot x-ray source; shifting each of the angularly displaced images with
respect to one another; adding each of the shifted images together to
reconstruct an image of a plane of the object; and inspecting the
reconstructed image plane to identify the presence or absence of a defect
in the object.

30. The method of claim 29, wherein the multiple focal spot x-ray source
is configured to generate the at least two x-ray beams via current flow
established between an anode and a cathode.

31. The method of claim 29, wherein inspecting the reconstructed image
plane comprises comparing the reconstructed plane to a reference plane to
identify one or more differences between the reconstructed plane and the
reference plane.

32. The method of claim 29, wherein the stationary multiple focal spot
x-ray source is configured to remain stationary with respect to
rotational and translational movement.

33. The method of claim 29, wherein the series of angularly displaced
images are obtained over an angle approximately equal to 40 degrees.

34. The method of claim 29, comprising applying a deblurring algorithm to
the reconstructed plane image to substantially reduce the background
effects of out of focus planes prior to inspecting the reconstructed
plane image for the presence or absence of defects.

35. The method of claim 29, further comprising adding each of the shifted
images together to reconstruct a second image of a second plane of the
object.

36. The method of claim 35, further comprising determining a thickness of
the object based on the image of the plane of the object and the second
image of the second plane of the object.

37. A laminography inspection system, comprising: a multiple focal spot
x-ray source configured to irradiate an object with a series of angularly
displaced x-ray beams one at a time without substantial rotation or
translation of the multiple focal spot x-ray source, wherein the multiple
focal spot x-ray source is disposed on a first side of the object; a
detector configured to receive at least a fraction of the angularly
displaced x-ray beams after being attenuated by the object to produce at
least two x-ray projection images of the object, wherein the detector is
disposed on a second side of the object opposite the first side; and a
processor configured to process the at least two x-ray projection images
to bring at least two planes of the object into focus, one at a time.

38. The laminography inspection system of claim 37, wherein the detector
is a digital flat panel detector.

39. The laminography inspection system of claim 37, wherein the processor
is further configured to accept, reject, or flag the object based on a
comparison of the at least two focused planes with a reference.

40. The laminography inspection system of claim 37, wherein the object is
at least one of a pipe, a pipe array, a wind blade, a wind blade spar
cap, and a printed circuit board with discrete components.

41. The laminography inspection system of claim 37, wherein the processor
is configured to shift and add the at least two projection images to
bring the at least two planes of the object into focus, one at a time.

[0002] Many industrial applications rely on radiological inspection
techniques to determine the quality of industrial parts, such as pipes,
pipe arrays, fan blades, wind blade spar caps, and so forth. Such
inspection techniques may also be utilized to determine one or more
features of an object, such as to determine the wall thickness of a pipe.
Since these industrial applications often require inspection of an entire
object for quality control purposes, the x-ray sources typically employed
in such applications are associated with a mechanical gantry. Each time
the mechanical gantry moves the x-ray source to a new location, another
image is taken, and a series of such images is typically used to
determine the presence or absence of a defect in the part.

[0003] Unfortunately, the gantries associated with these single spot x-ray
sources are often complex and slow, thus reducing efficiency by
increasing the amount of time required to accept or reject a manufactured
object. Additionally, the complexity of such systems may lead to downtime
associated with necessary repairs and malfunctions. Furthermore, such
complex systems may be associated with a high monetary cost and a limited
field of view. Accordingly, there exists a need for improved laminography
inspection systems and methods that overcome such drawbacks.

BRIEF DESCRIPTION OF THE INVENTION

[0004] In one embodiment, an imaging system includes a multiple focal spot
x-ray source adapted to generate at least two x-ray beams and to project
each of the generated x-ray beams at a different angle, one at a time,
toward an object without substantial rotation or translation of the
multiple focal spot x-ray source. The multiple focal spot x-ray source is
disposed on a first side of the object. The imaging system also includes
a detector disposed on a second side of the object opposite the first
side. The detector is adapted to receive at least a fraction of the
projected x-ray beams from each of the different angles after being
attenuated by the object and to produce at least two x-ray projection
images of the object corresponding to each of the different angles. Each
of the x-ray projection images are adapted to be shifted with respect to
one another and added to reconstruct a plane of the object.

[0005] In another embodiment, a laminography inspection method includes
providing an object to an inspection area, irradiating the object with at
least two x-ray beams from at least two different angles, one at a time,
to generate a series of angularly displaced images of the object. The
x-ray beams are generated by a stationary multiple focal spot x-ray
source. The method also includes shifting each of the angularly displaced
images with respect to one another, adding each of the shifted images
together to reconstruct an image of a plane of the object, and inspecting
the reconstructed image plane to identify the presence or absence of a
defect in the object.

[0006] In another embodiment, a laminography inspection system includes a
multiple focal spot x-ray source adapted to irradiate an object with a
series of angularly displaced x-ray beams, one at a time, without
substantial rotation or translation of the multiple focal spot x-ray
source. The multiple focal spot x-ray source is disposed on a first side
of the object. The laminography inspection system also includes a
detector adapted to receive at least a fraction of the angularly
displaced x-ray beams after being attenuated by the object to produce at
least two x-ray projection images of the object. The detector is disposed
on a second side of the object opposite the first side. The laminography
inspection system also includes a processor adapted to shift and add the
at least two x-ray projection images to bring at least two planes of the
object into focus, one at a time.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects, and advantages of the present
invention will become better understood when the following detailed
description is read with reference to the accompanying drawings in which
like characters represent like parts throughout the drawings, wherein:

[0008]FIG. 1 illustrates an embodiment of a laminography imaging system
including a substantially stationary multiple focal spot x-ray source;

[0009]FIG. 2 illustrates a front view of the imaging system of FIG. 1
with a pipe positioned for imaging in accordance with embodiments of the
present invention;

[0010]FIG. 3 illustrates the imaging system of FIG. 2 after generation of
a first x-ray beam in accordance with embodiments of the present
invention;

[0011]FIG. 4 illustrates the imaging system of FIG. 2 after generation of
a second x-ray beam in accordance with embodiments of the present
invention;

[0012]FIG. 5 illustrates the imaging system of FIG. 2 after generation of
a third x-ray beam in accordance with embodiments of the present
invention;

[0013]FIG. 6 illustrates a front view of the imaging system of FIG. 1
with a pipe array positioned for imaging in accordance with embodiments
of the present invention;

[0014]FIG. 7 illustrates the imaging system of FIG. 6 after generation of
a first x-ray beam in accordance with embodiments of the present
invention;

[0015]FIG. 8 illustrates the imaging system of FIG. 6 after generation of
a second x-ray beam in accordance with embodiments of the present
invention;

[0016]FIG. 9 illustrates the imaging system of FIG. 6 after generation of
a third x-ray beam in accordance with embodiments of the present
invention;

[0018]FIG. 11 illustrates a laminography inspection method that may be
utilized to operate the imaging system of FIG. 1 in accordance with
embodiments of the present invention; and

[0019]FIG. 12 illustrates a processing method that maybe utilized to
process the image data acquired during the method of FIG. 11 in
accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] As described in detail below, embodiments of imaging systems
including a substantially stationary multiple focal spot x-ray source
that generates angularly displaced x-rays that irradiate an object before
being detected by a detector are provided. Such systems may be capable of
remaining substantially stationary while obtaining a complete set of
planar images of an object over an arc; the set of planar images may be
utilized to reconstruct slices at different planes in the object. For
example, in one embodiment, a processor of a laminography inspection
system may utilize the set of planar images to reconstruct slices of a
pipe, determine a wall thickness of a pipe, and determine the presence
and location of a defect in the pipe. Further, in some embodiments, the
slices of the object (e.g., a pipe) may be reconstructed via a
shift-and-add procedure and, subsequently, mathematical deblurring
techniques may be used to improve the image quality and slice sensitivity
profile.

[0021] The foregoing features of embodiments of the present invention may
offer advantages over existing single focal spot x-ray source inspection
systems. For example, the use of a multiple focal spot x-ray source may
increase the speed of the inspection process. That is, multiple focal
spot x-ray sources are capable of rapidly obtaining multiple images by
activating each focal spot, one at a time, in rapid succession, thereby
eliminating the need for gantry movement time. Each of the focal spots in
such an x-ray source is electronically addressable in a specific manner,
thus allowing each focal spot to be activated and deactivated quickly
(e.g., within 1 microsecond, within 100 microseconds, within 1000
microseconds, etc.). Such features may reduce the length of time
necessary to detect and characterize a defect in an industrial product.

[0022] Furthermore, the systems disclosed herein may offer additional
advantages over single spot x-ray sources, such as the scalability of the
generated power. For instance, in one embodiment, each focal spot of the
multiple focal spot x-ray source may have an average power of
approximately 600 Watts and, accordingly, a ten focal spot x-ray source
may have a total power of approximately 6000 Watts. Such a total power
may be approximately six times greater than many typical single spot
x-ray sources. Indeed, such multiple focal spot x-ray sources may offer
many distinct advantages over traditional single spot systems.

[0023] Turning now to the drawings, FIG. 1 illustrates a laminography
imaging system 10 that is adapted to obtain a variety of projection
images of an object 12 over an angular range without substantial motion
of a multiple focal spot x-ray source 14. To that end, the system
includes the multiple focal spot x-ray source 14 with focal spot 16, the
object 12 disposed on an inspection board 18 in a field of view of the
x-ray source, a detector 20, and an image control and processing system
22 including memory 24. In the illustrated embodiment, an x-ray beam 26
is shown projected from the focal spot 16, into the field of view, and
through the object 12 onto the detector 20. However, it should be noted
that although in FIG. 1, only a single focal spot 16 is shown, multiple
focal spots may be located adjacent to focal spot 16 in some embodiments,
as described in more detail below. In such embodiments, each focal spot
may be configured to function as a module providing a distinct field of
view, and, accordingly, a multiple focal spot source may be used in a
plane to increase the overall field of view as compared to single focal
spot sources.

[0024] During operation, the multiple focal spot source 14 generates the
x-ray beam 26 from the first focal spot 16. The x-ray beam 26 is
projected onto the object 12, which attenuates the beam 26 before it
reaches the detector 20. As such, the detector 20 receives a fraction of
the projected x-ray beam 26 after being attenuated by the object 12. In
the illustrated embodiment, the detector 20 is a flat panel digital
detector that digitizes the received converted x-ray energy and exports
such digitized data to the image control and processing system 22. The
image control and processing system 22 is adapted to convert the
digitized data into a first projection image and to store the first
projection image to the memory 24 for future retrieval and/or processing.
In some embodiments, the image control and processing system 22 may
process the first projection image before storing it to memory.

[0025] Subsequently, while remaining substantially stationary, the
multiple focal spot x-ray source 14 generates additional x-ray beams, one
at a time, from distinct focal spots disposed over a predefined arc. That
is, without substantial rotational or translational movement, the
multiple focal spot x-ray source projects x-ray beams at a variety of
different angular positions. As before, each of the x-ray beams originate
from a focal spot in the substantially stationary x-ray source 14,
project through the object 12, and impinge the detector 20, where they
are each converted to a separate projection image acquired at a different
angle about the predefined arc. The generated set of planar images
obtained over the arc may then be utilized by the image control and
processing system 22 to reconstruct slices of the object 12 at different
planes.

[0026] For example, in one embodiment, the digital projection images
acquired at distinct angular positions are shifted and then summed a
desired number of times to bring multiple depths of the object into
focus, one at a time. In this embodiment, different shift distances may
be utilized to reconstruct different planes in the volume of the object
12. For example, by adding the acquired projection images without
applying a shift distance, the focal plane of the object 12 that is
coincident with the focal plane of the scan may be reconstructed by the
image processing system 22. For further example, by shifting each image
by another set of first distances, which are determined based on the
system geometry, and subsequently adding the shifted images, a second
focal plane of the object 12 may be brought into focus. Using this
approach, the image processing system 22 may reconstruct all the planes
of interest in the acquisition volume. Subsequently, the processing
system 22 may apply one or more mathematical deblurring techniques to
each of the reconstructed planes to improve the image quality by removing
image artifacts from out of focus planes. As described in more detail
below with respect to FIGS. 11 and 12, such reconstructed and processed
image slices may be further utilized by the control and processing system
22, for example, to determine the presence or absence of one of more
defects in the object 12.

[0027] In some embodiments, after a set of projection images are acquired
over the predefined arc, the object 12 may be translated, as indicated by
arrow 26, and the described procedure may be repeated at the next
location along the length of the object. In further embodiments, the
multiple focal spot x-ray source 14 may be translated, as indicated by
arrow 28, to another location along the length of the object, and the
described procedure may be repeated. That is, a second set of images may
be acquired over the given arc at the next lengthwise position of the
object 12 and the additional image set may be used to reconstruct
additional slices at distinct planes in the object. However, each time
the multiple focal spot x-ray source 14 is positioned to image the
object, the source 14 remains stationary (i.e., does not rotate or
translate) while acquiring a complete set of projection images over the
desired angular range.

[0028] FIGS. 2-5 illustrate front views of the imaging system 10 of FIG. 1
during an example mode of operation that may be utilized to acquire a set
of projection images over a given arc that may then be utilized to
reconstruct the desired object slices at different planes. Specifically,
FIG. 2 illustrates the initial setup prior to image acquisition. In this
embodiment, the imaging setup includes the multiple focal spot x-ray
source 14, the detector array 20, and a pipe 30 disposed between the
x-ray source 14 and the detector 20 for imaging. The multiple focal spot
x-ray source 14 includes the first focal spot 16, a second focal spot 32,
a third focal spot 34, a fourth focal spot 36, a fifth focal spot 38, a
sixth focal spot 40, and a seventh focal spot 42.

[0029] During operation, the x-ray source 14 is adapted to selectively
activate each of the focal spots to obtain a set of projection images of
the pipe 30. For example, FIG. 3 illustrates acquisition of a first
projection image of the pipe 30. As shown, the first focal spot 16 is
activated to produce the first x-ray beam 26. The first x-ray beam 26 is
projected through the pipe 30, and the detector array 20 detects at least
a portion of the x-ray beam 26. The detector 20 generates a digital
representation of the detected x-rays, which is exported to the
processing system for storage and processing.

[0030]FIG. 4 illustrates acquisition of a second projection image of the
pipe 30, which is obtained without substantial rotation or translation of
the x-ray source 14 and without substantial rotation or translation of
the detector 20 or object 30. As illustrated, the fourth focal spot 36 is
activated to produce a second x-ray beam 44 that is projected toward the
pipe 30. The second x-ray beam 44 is attenuated by the pipe 30 before
being detected by the detector array 20. As before, the detector array 20
digitizes the detected x-rays to generate a second projection image that
is exported for further processing and storage.

[0031]FIG. 5 illustrates acquisition of a third projection image of the
pipe 30, which is again obtained without substantial movement of the
x-ray source 14, the detector 20, or the object 30. During acquisition of
the third projection image, the seventh focal spot 42 is activated to
produce a third x-ray beam 46 that is directed toward the pipe 30. The
third x-ray beam 46 is attenuated by the pipe 30 before impinging on the
detector array 20 and being converted into the third projection image. In
this way, three projection images of the pipe 30 may be acquired by the
imaging system without substantial movement of the multiple focal spot
x-ray source 14 the detector 20, or the object 30.

[0032] In the illustrated embodiment, the three acquired projection images
form a single set of images acquired over a single arc that may be
utilized to reconstruct multiple planes of interest in the acquisition
volume of the pipe 30. It should be noted, however, that in further
embodiments, any desired number of focal spots may be provided in the
stationary x-ray source 14 and activated to produce any desired number of
images over the given arc range. For example, in the illustrated
embodiment, each of the seven focal spots may be activated to produce
seven projection images in a single acquisition set. Further, the images
may be acquired over any desired angular range (e.g., 20 degrees, 30
degrees, 40 degrees, etc.). However, as described in detail above, a
shift-and-add procedure may be performed on each acquisition set to
reconstruct the desired planes within the pipe 30.

[0033] FIGS. 6-9 illustrate front views of the imaging system 10 of FIG. 1
during an example mode of operation that may be utilized to acquire a set
of projection images of an array of objects. Specifically, FIG. 6
illustrates the initial setup prior to image acquisition. In this
embodiment, the imaging setup includes the multiple focal spot x-ray
source 14, the detector array 20, and an array of pipes 48 disposed
between the x-ray source 14 and the detector 20 for imaging. The array of
pipes 48 includes a first pipe 50, a second pipe 52, a third pipe 54, and
a fourth pipe 56. As before, the multiple focal spot x-ray source 14
includes focal spots 16, 32, 34, 36, 38, 40, and 42.

[0034] During operation, the x-ray source 14 selectively activates each of
the focal spots to obtain a set of projection images of the pipe array
48. For example, FIG. 7 illustrates acquisition of a first projection
image of the pipe array 48. As shown, the first focal spot 16 is
activated to produce a first x-ray beam 58. The first x-ray beam 58 is
projected through the pipe array 48, and the detector array 20 detects at
least a portion of the x-ray beam 58 after attenuation through pipes 50,
52, and 54. The detector 20 generates a digital representation of the
detected x-rays, which is exported to the processing system for storage
and subsequent processing.

[0035]FIG. 8 illustrates acquisition of a second projection image of the
pipe array 48, which is obtained without substantial rotation or
translation of the x-ray source 14, the detector 20, or the objects 50,
52, 54, 56, 58. As illustrated, the fourth focal spot 36 is activated to
produce a second x-ray beam 60 that is projected toward the pipe array
48. The second x-ray beam 60 is attenuated by each of the pipes 50, 52,
54, and 56 in the pipe array 48 before being detected by the detector
array 20. As before, the detector array 20 digitizes the detected x-rays
to generate a second projection image that is exported for further
processing and storage.

[0036]FIG. 9 illustrates acquisition of a third projection image of the
pipe array 48, which is again obtained without substantial movement of
the x-ray source 14, the detector 20, or the objects 50, 52, 54, 56, 58.
During acquisition of the third projection image, the seventh focal spot
42 is activated to produce a third x-ray beam 62 that is directed toward
the pipe array 48. The third x-ray beam 62 is attenuated by pipes 52, 54,
and 56 before impinging on the detector array 20 and being converted into
the third projection image. In this way, as before with the single pipe
system of FIGS. 2-5, three projection images of the pipe array 48 may be
acquired by the imaging system without substantial movement of the
multiple focal spot x-ray source 14, the detector 20, or the objects 50,
52, 54, 56, 58. Additionally, in the illustrated embodiment, the three
acquired projection images form a single set of images acquired over a
single arc that may be utilized to reconstruct multiple planes of
interest in the acquisition volume of the pipe array 48.

[0037]FIG. 10 illustrates an embodiment of the multiple focal spot x-ray
source 14 shown in FIGS. 1-9. However, it should be noted that such an
embodiment is merely an example, and any suitable multiple focal spot
x-ray source may be utilized in the stationary imaging systems described
herein. In the illustrated embodiment, the x-ray source 14 includes a
controller 64, a plurality of cathodes 66, a plurality of anodes 68, a
high voltage and oil feedthrough 70, and a vacuum chamber 72. The
plurality of anodes includes a first anode 74, a second anode 76, a third
anode 78, a fourth anode 80, and a fifth anode 82. The plurality of
cathodes includes a first cathode 84, a second cathode 86, a third
cathode 88, a fourth cathode 90, and a fifth cathode 92. The controller
is coupled to the first anode 74 via control lines 94, to the second
anode 76 via control lines 96, to the third anode 78 via control lines
98, to the fourth anode 80 via control lines 100, and to the fifth anode
82 via control lines 102.

[0038] During operation, the plurality of cathodes 66 emit electrons into
the vacuum chamber 72, and the electrons are collected by the plurality
of anodes 68, thus establishing electron beams 104, 106, 108, 110, and
112 through the x-ray tube 14. As the electrons originate from the
plurality of cathodes 66 and collide with the plurality of anodes 68,
energy is generated and emitted as x-rays, for example, in a direction
perpendicular to the electron beams 104, 106, 108, 110, and 112. The high
voltage and oil feedthrough 70 accelerates the electrons as they flow
through the x-ray tube. The controller 64 controls each of the anodes
individually to control x-ray generation such that the previously
described sets of projection images may be acquired.

[0039]FIG. 11 illustrates a laminography inspection method 114 that may
be utilized to operate the imaging system of FIG. 1. The method 114
includes providing an object to the inspection area (block 116), for
example, providing a pipe to an inspection area. The method 114 also
includes irradiating the object at a desired angle with a stationary
multiple focal spot x-ray source (block 118) and, after the x-rays are
attenuated by the object, detecting at least a portion of the x-rays on
the detector array (block 120). The acquired x-ray projection data is
also stored (block 122), for example, to a memory of a control or
processing system. The object is then irradiated at a variety of
additional angles to obtain additional projection images while
maintaining the x-ray source substantially stationary (block 124).

[0040] In the illustrated method, the object is subsequently translated
(block 126) and again irradiated at a plurality of angles to obtain
another set of projection images at the second lengthwise location along
the length of the object (block 128). However, it should be noted that
during acquisition of the set of projection images, the multiple focal
spot x-ray source remains substantially stationary with respect to
rotational and translational movement. The acquired x-ray data along the
length of the object is then processed (block 130), and a determination
is made as to whether the object is accepted, rejected, or flagged (block
132). That is, the object is inspected for the presence or absence of a
defect, such as stress corrosion on a pipe.

[0041] In one embodiment of the above method, if the object fits within
the boundary of the source detector active regions, there may be no
movement of the object necessary to obtain laminographic data and to
reconstruct planes of the object. In such embodiments, the virtual motion
of the source may substitute for the motion of the object. As such,
certain embodiments may be substantially stationary in that no moving
parts are necessary, thus possibly reducing the complexity and monetary
expense associated with making and operating the disclosed imaging
systems.

[0042]FIG. 12 illustrates an embodiment of the processing step of FIG.
11. The processing method 130 includes providing the acquired projection
data to a processor (block 134). For example, a single set of projection
data taken over a given angular range at one lengthwise location along
the length of the object may be provided to the processor. The method 130
also includes shifting each acquired image within the set of projection
data by a desired amount for the reconstruction of a first plane (block
136) and adding each shifted image to produce an unprocessed first plane
(block 138). That is, as described above, the acquired projection images
may be shifted and added to produce slices of the object at various
volumetric depths. If desired, one or more deblurring or processing
techniques may be utilized to remove out of focus artifacts to produce a
processed first plane (block 140). The processed first plane may be
compared to a reference to determine the presence or absence of a defect
(block 142). To reconstruct additional planes, the projection images
within a given set may again be shifted by a second desired amount, added
together, and processed to produce images of additional planes at
different depths through the object (block 144).

[0043] Technical effects of embodiments of the invention include an
increased inspection speed as compared to traditional systems. That is,
the multiple focal spot x-ray systems disclosed herein are capable of
electronically addressing each of the focal spots in a specific manner,
thus allowing each focal spot to be activated and deactivated quickly
(e.g., within 1 microsecond). Such features may reduce the length of time
necessary to detect and characterize a defect in an industrial product.
Further, the systems disclosed herein may offer additional technical
advantages over single spot x-ray sources, such as the scalability of the
generated power. The total power capable of being generated by
embodiments of present invention may be substantially greater than many
typical single spot x-ray sources. Additionally, in embodiments in which
an object size fits within the active regions of the source detector
configuration, movement of the x-ray source, the object, or the detector
may not be necessary, thus possibly reducing or eliminating motion blur.

[0044] This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in the art
to practice the invention, including making and using any devices or
systems and performing any incorporated methods. The patentable scope of
the invention is defined by the claims, and may include other examples
that occur to those skilled in the art. Such other examples are intended
to be within the scope of the claims if they have structural elements
that do not differ from the literal language of the claims, or if they
include equivalent structural elements with insubstantial differences
from the literal languages of the claims.